Tan Jumping Spider, Familiar Jumping Spider
Platycryptus undatus
Salticidae (Jumping Spiders), Order Araneae
Physical Description
A stout, flattened jumping spider with a somewhat rectangular cephalothorax. The abdomen is elongated and slightly wider than the head. The body is covered in short, dense hairs that provide a velvety texture, with longer sensory hairs (setae) protruding.
Size Estimate
The specimen appears to be an adult female, approximately 10-13mm in body length with a leg span of 20-25mm. Males are slightly smaller and more slender.
Coloration & Markings
Mottled grey, tan, and brown tones designed for camouflage on bark. The abdomen features a prominent, dark, undulating or 'zig-zag' pattern down the center, flanked by lighter patches. Subtle orange or red hairs may be visible around the eyes.
Web Type
This is an active hunting spider and does not build a web to catch prey. It produces silk 'pup-tents' or silken retreats for molting, mating, and sleeping in crevices or under bark.
Eye Arrangement
Typical Salticid pattern: 4 pairs of eyes. Two very large Anterior Median Eyes (AME) provide high-resolution, telescopic color vision, flanked by smaller Anterior Lateral Eyes (ALE). Four smaller eyes are situated on the top and sides of the cephalothorax.
Leg Characteristics
The legs are relatively short, thick, and powerful, adapted for jumping rather than running. They are covered in fine hairs and spines, with distinct dark banding. The front legs are slightly more robust for grasping prey.
Venom & Safety Information
Venom Information
The venom is a complex mixture designed to paralyze small insects quickly. It is not considered medically significant to humans; its toxicity is very low for mammals.
Medical Significance
Harmless. Bites are extremely rare and usually occur only if the spider is pinned against skin. Symptoms are typically milder than a bee sting, involving slight redness or localized itching that resolves quickly.
Safety Recommendations
No special safety measures are needed. If found indoors, they can be easily moved outside by placing a cup over them and sliding a piece of paper underneath. They are beneficial roommates that eat household pests.
Habitat & Behavior
Habitat & Range
Common across North America, particularly in the Eastern United States and Canada. They are frequently found on vertical surfaces like tree trunks, fence posts, and the exterior walls of houses.
Behavior & Temperament
Highly intelligent and curious hunters with a calm temperament. They track prey visually rather than through vibrations. When approached by humans, they often tilt their heads to observe the person or jump away only as a last resort.
Diet & Prey
Carnivorous generalists that eat flies, crickets, moths, and other small arthropods. They use their keen eyesight to stalk prey from a distance before delivering a precise, high-speed pounce.
Seasonal Activity
Most visible from spring through autumn. They are often seen sunning themselves on walls during warm days in late summer and fall as they prepare for the mating season.
Description
The Tan Jumping Spider is a charismatic, flattened spider that is masterfully camouflaged for life on wood and bark. Known for its 'friendly' demeanor and incredible jumping ability, it is a favorite among arachnologists for its expressive movements and visual acuity.
Key Features
Distinctive undulating zig-zag pattern on the dorsal abdomen, flattened body profile, and the classic large, forward-facing 'binocular' eyes characteristic of jumping spiders.
Similar Species
Members of the genus Marpissa look similar but tend to have more elongated bodies. Platycryptus californicus is very similar but occupies the Western United States and Canada.
Life Cycle
Females lay eggs in silken sacs hidden in crevices. They often guard the sac until the spiderlings emerge. Spiderlings disperse via 'ballooning' on silk threads. The typical lifespan is about one year, including overwintering as sub-adults.
Ecological Importance
As an apex predator of the micro-world, they provide excellent natural pest control, consuming significant numbers of mosquitoes and agricultural pests.
Conservation Status
Not evaluated by the IUCN, but considered common and stable throughout its range with no immediate conservation threats.
Interesting Facts
Jumping spiders have the best vision of any invertebrate. They use a 'dragline' of silk like a bungee cord whenever they jump, ensuring they don't fall if they miss their target or the surface is slick.
Photography Tips
Focus primarily on the face to capture the large eyes, which creates an engaging portrait. Use a macro lens or close-up mode. Because they are curious, they will often sit still and 'pose' if you move slowly.
Identified: 2026-05-31T22:16:01.570077